STATUS: AVAILABLE FOR FULL-STACK & FRONTEND ROLES

Hello, I'm Ivan Kahan.

I specialize in building high-performance web applications, Chrome extensions, and mobile apps. Currently designing e-commerce modules, AI SaaS integrations, and advanced BDD testing suites.

Ivan Kahan
01 // CAREER PROGRESSION

Professional Experience

[SP]

SP-Lutsk

3 yrs 10 mos · Ukraine (Hybrid / On-site / Remote)

Jul 2026 – PresentFull-time · On-site

Full Stack Engineer

Extended past the API boundary — taking features from data model and endpoint design through to the interface that consumes them:

  • Deepened into backend work — Django services, data modelling, and the async-job infrastructure behind them — while continuing to lead frontend architecture.
  • Ship features end-to-end on the products I own, which changed how I scope work: constraints in the data model surface before the UI is designed around them, not after.
Oct 2022 – Jun 20263 yrs 9 mos · Full-time · Hybrid

Frontend Developer

Moved from implementing designs to owning frontend architecture across several production SaaS products:

  • Progressed from building screens and reusable components to leading a full framework & TypeScript migration on a production platform, then maintaining the patterns it introduced.
  • Rebuilt a large client-rendered SPA on a modern App Router architecture, where routing, i18n, state persistence, and auth all had to be re-thought rather than ported — the old assumptions broke quietly under server rendering, not loudly.
  • Took performance on as a discipline rather than an afterthought — measuring Core Web Vitals and fixing what the numbers pointed at: render-blocking resources, layout shift, and third-party scripts nobody had audited in years.
  • Learned to chase the bugs that leave no stack trace — hydration mismatches, effects re-firing on unstable references, code that only misbehaves once it runs somewhere it was never written to run.
  • Grew comfortable owning the parts nobody volunteers for: legacy migrations, cross-browser edge cases, and test coverage.
Nov 2022 – Jun 20238 mos · Part-time · Remote

QA Engineer

Where I started — building the automation that proves a system holds up before users find out it doesn't:

  • Built the load-testing and end-to-end automation foundation — k6 scenarios for throughput, browser suites covering the flows that cost money when they break, and Grafana dashboards over InfluxDB so the numbers were visible rather than buried in CLI output.
  • Wrote those scenarios against a shared environment that never sat still, which taught me early that a test asserting on exact state is a test that will eventually fail for the wrong reason.
  • Sat between developers and the product on triage, where I learned to write a report someone can act on without a follow-up question.
  • Spent eight months watching how production systems actually break — the instinct for failure modes I still lean on when writing and reviewing code came from here.
02 // SELECTED PRODUCTS

Featured Projects & Products

[ CHROME EXTENSION // MANIFEST V3 ]

AliExpress Orders Exporter

A secure, private Manifest V3 Chrome Extension & Next.js dashboard. Features synchronous MAIN world network interception, HAR package offline imports, price trend tracking, dispute rate metrics, automated PDF invoice compilation, and Google Sheets OAuth2 synchronization.

Chrome Extension (MV3)React 19Next.js 16TypeScriptIndexedDBGoogle Sheets APIesbuildTailwind CSS v4Vitest
[ SaaS Logistics ]

SKzxlop

A multi-tenant logistics & supply chain platform. Led frontend delivery of its largest subsystems — multi-warehouse operations, quoting, and vendor SKU mapping — plus Amazon SP-API & DocuSign integrations, shipping calculators, and dynamic PDF shipping labels.

ReactTypeScriptRedux ToolkitRTK QueryReact RouterReact Hook FormWebSocketsCalendly APIStripeCypressCucumberk6GrafanaAmazon SP-APIDocuSign APIHubSpot APIDjangoPostgreSQLDockerKubernetes
[ SaaS Ecommerce ]

Clwxpzqber

A multi-tenant e-commerce order fulfillment & dropshipping platform. Architected multi-role order processing workflows, product catalog management, and automated billing balances. Built the real-time AI support chat (WebSocket) and the k6 load-testing suite covering admin, tenant, and shared flows.

ReactTypeScriptRedux ToolkitReact RouterReact Hook FormWebSocketsOpenAI APIStripePayPalPlaywrightk6Amazon SP-APIShopify APIDjangoPostgreSQLDockerAWS
[ AI SaaS Platform ]

juaxkzwprqmvy.ai

An AI headshot & avatar generation platform. Contributed to checkout promo logic, plan usage dashboards, Sanity CMS landing pages, and OpenAI/fal.ai image-generation workflows.

ReactNext.jsTypeScriptRedux ToolkitReact RouterStripePayPalFirebaseTailwind CSSSanity CMSOpenAI APIfal.aiDjangoDjango Ninja
[ Developer Portal ]

qrtznwblshpxd.com

A high-traffic dynamic QR code SaaS platform. Architected the complete Next.js (App Router) & TypeScript migration, built subscription cancellation/win-back flows, integrated Stripe & PayPal multi-tier checkout, and optimized Core Web Vitals.

Next.jsReactTypeScriptRedux ToolkitReact Hook FormStripePayPalFirebase AuthTailwind CSSDjangoDjango NinjaPostgreSQLDockerSentry
[ Hardware Analytics ]

li-ion-calculator

A high-performance balancing calculator for custom lithium-ion battery packs. Built an off-thread Web Worker optimization engine (Genetic Algorithms), thermal heatmap simulations, busbar connection layout pathing, multi-format file parsers, and IndexedDB workspace management.

Next.jsReactTypeScriptWeb WorkersTailwind CSSSheetJS (XLSX)IndexedDBVitest
[ Mobile Application ]

fiqwzbncxvlksdher

A full-stack personal finance & expense tracking mobile app I contributed to, built with React Native (Expo Router v6), NativeWind, and Django REST microservices. Features voice expense logging (Whisper AI), Tesseract OCR receipt scanning, Celery/Redis async task queues, WebSockets, and Stripe billing.

React NativeExpo RouterTypeScriptRedux ToolkitReact NavigationWebSocketsStripeNativeWindTesseract OCRDjango RESTCeleryRedisPostgreSQLDockerNginx
[ SaaS Analytics ]

sanzkxwpqrmvyai

An AI-powered Sankey diagram & flow visualization SaaS platform. Built native Microsoft Excel Add-in data sync, automated AI diagram generation (OpenAI), drag-and-drop node editing, and Stripe & PayPal multi-tier subscription billing.

Next.jsReactTypeScriptRedux ToolkitOffice Add-in APIsStripePayPalFirebaseTailwind CSSOpenAI APIDjangoDjango NinjaPostgreSQLDockerSentry
[ SEO Blog Platform ]

qrbzkxwpqrmvyog

Multilingual content hub featuring AI-powered automated post generation and translations. Integrated SEO routing systems, smart CDN asset resizing, and a Core Web Vitals pass now measuring 96 mobile performance and 100 SEO on PageSpeed Insights.

Next.jsReactTypeScriptOpenAI APIClaude APIAI AutomationGoogle Cloud TranslationCDN Image ResizerPostgreSQLGoogle CloudDocker
[ Inventory Database ]

lab-inventory

A local-first laboratory antibody inventory tracking app. Features dynamic inventory usage tracking, report validation routines, and Excel spreadsheet export support.

Next.jsFirebaseFirebase FunctionsFirebase Admin SDKReact Hook FormReact ToastifyTypeScriptxlsx (SheetJS)
[ Full Stack CRM ]

beauty-crm

A full-stack salon management & client scheduling CRM. Built real-time appointment booking updates (Express-WS & WebSockets), JWT authentication with HTTP-only cookies, client interaction histories, and responsive Redux Toolkit dashboards.

ReactRedux ToolkitReact RouterReact Hook FormNode.jsExpress.jsWebSocketsJWT AuthMongoDBMongooseBootstrap
[ Web Planner ]

calendar-project

An interactive web planner modeled after Google Calendar. Built multi-view scheduling grids, custom date algorithms (Day.js), and real-time cloud sync with Firebase Firestore. Developed as the portfolio project that secured my first professional developer role.

ReactRedux ToolkitReact RouterReact BootstrapAxiosDay.jsFirebaseFirestoreBootstrap
[ Mobile Assistant ]

LNTU-Assist

A university mobile assistant for Lutsk National Technical University. Built campus map navigation (react-native-maps), schedule lookups, and audio playback (expo-av). My foundational project, self-taught from scratch on the fly.

React NativeExpoReduxReact NavigationReact Native MapsExpo AVAxiosAndroid/iOS
03 // ENGINEERING NOTES

Problems Solved

[AliExpress Orders Exporter]Chrome MV3

No API tells you if a background tab finished, got blocked, or is stuck

The extension opens a hidden tab to let AliExpress's own page load and capture data — but there's no signal for whether that tab finished normally, hit a login wall, got a captcha, or is just slow. Naive detection matched anti-bot script tags and words like 'verify' that are present on every single page, not just blocked ones.

[AliExpress Orders Exporter]Chrome MV3 · MAIN world

A network-interception result couldn't cross back out of the page's own execution context

Capturing AliExpress's own network requests meant hooking fetch/XHR inside the page's MAIN world, running before the page's own code — but whatever that hook captured couldn't be handed directly to the extension's isolated content-script world; the two contexts don't share objects.

[SKzxlop]Carrier APIs + Redux

Tracking one shipment took a chain of four dependent API calls

Neither carrier provider answered in a single request — one returned a job id the browser had to poll, the other a numeric status code and a latitude field that sometimes read "Not Supported". Turning that into a map position needed geocoding and route interpolation on top, and the entire list had to settle before anything rendered, with every intermediate state passing through one hand-rolled Redux store.

[SKzxlop]Django + Kubernetes

Notifications lie about job completion

Amazon product imports run as Kubernetes Jobs. The completion notification is written from inside the pod before the container actually exits — so it can reach the browser while Kubernetes still reports the job as running.

[SKzxlop]k6 load testing

Load tests that assumed a linear timeline

Load-testing a shared, constantly-mutating environment breaks any suite that assumes 'test B runs after test A creates its data' — at real concurrency, that assumption never holds.

[qrtznwblshpxd.com]Next.js / reverse proxy

A page couldn't start rendering until the entire upstream response finished downloading

The reverse proxy in front of the blog buffered the full upstream response before forwarding it, so time-to-first-byte was gated on downloading the whole HTML document first — no matter how fast the visitor's connection was.

[qrbzkxwpqrmvyog]AI content pipeline

A single AI generation call routinely outlasted what the platform allowed

Generating a blog post with AI could take longer than a normal request/response call is allowed to run — and even after switching to a streaming response, the connection could still be dropped after a period of inactivity regardless of the overall time budget, with default compression occasionally corrupting the tail of the stream on disconnect.

[qrbzkxwpqrmvyog]Next.js / image pipeline

Turning image optimization back on wasn't enough to actually get it

Image optimization had been disabled outright. Re-enabling it looked like the whole fix — but the blog is served behind another app through a path rewrite, and without an explicit optimizer path the generated image URLs resolved to the parent app's unoptimized endpoint. In production the images were served exactly as before, with nothing in the build or the page to flag it.

[sanzkxwpqrmvyai]Excel Add-in

Office Add-in tooling doesn't support Next.js

Microsoft's Add-in template and CLI only scaffold a plain React/webpack app — there's no supported path to run an Add-in on Next.js.

04 // TECHNICAL STACK

Core Skills

Languages & Runtimes

  • TypeScript / JavaScript (Node.js / Express.js)
  • Python (Django / Django Ninja)
  • SQL & NoSQL (PostgreSQL / MongoDB / Redis / SQLite)

Frontend & Mobile

  • React 18/19 & Next.js (App Router)
  • React Native (Expo / Expo Router)
  • Redux Toolkit & RTK Query state management
  • Tailwind CSS v4 & Modern CSS
  • Bootstrap & Modern Responsive Layouts
  • Internationalization (i18next / react-intl)

DevOps & Infrastructure

  • Docker & Docker Compose containerization
  • GitHub Actions CI/CD workflows automation
  • Sentry error monitoring & performance tracking
  • Cloudflare Workers serverless deployment

Specialized Integrations & AI

  • OpenAI API, Claude API & Antigravity
  • Microsoft Office Add-ins (Excel APIs)
  • Chrome Extension APIs (Manifest V3)
  • Stripe & PayPal Checkout Systems
  • ShipsGo, ParcelsApp, UPS & FedEx Carrier Tracking APIs
  • Calendly API Integration

QA, Testing & Automation

  • Playwright Browser E2E Automation
  • k6 Load & Performance Testing
  • Grafana & InfluxDB Load-Test Metrics Dashboards
  • Cypress & Cucumber BDD testing frameworks
  • Vitest & Jest Unit Test Suites

Data, Storage & Processing

  • IndexedDB Local-First Storage & Web Workers
  • SheetJS (XLSX) & Automated CSV/Excel Exports
  • Automated PDF Generation & Document Processing
  • RESTful APIs & OAuth2 Authentication Flows
  • WebSockets Real-Time Updates (react-use-websocket)

Design & Collaboration

  • Figma (UI/UX design, prototyping & dev handoff)
  • Jira, Clockify & If-team Workflows
  • Git & GitHub version control